(1) Field of the Invention
The present invention relates to methods of fabricating a metal-insulator-metal capacitor, and more particularly, to methods of forming metal-insulator-metal capacitors for embedded DRAM applications wherein contact etch depth is reduced in the fabrication of an integrated circuit device.
(2) Description of the Prior Art
In merging logic circuits and dynamic random access memory (DRAM) arrays on a single chip, compatibility is the primary issue with respect to both design and fabrication. Recently, with the continued decrease in device dimensions, it has become increasingly important to find solutions to problems that are caused by etching high aspect ratio contact openings. The DRAM capacitor's height must be increased in order to meet the high capacitance requirement. Meanwhile, in order to achieve a high dielectric constant for a metal-insulator-metal (MIM) or metal-insulator-silicon (MIS) capacitor, the dielectric material should be deposited at high temperature (of more than about 600° C.) or annealed at high temperature after film deposition. Thus, the capacitor formation must be completed before the copper/low dielectric constant (k) material process. But this limitation will impact contact etching because of device dimension shrinkage. Because of the high capacitance requirement, the height of the capacitor cannot be reduced. However, we can try to improve the contact high aspect ratio etch problem in other ways. U.S. Pat. Nos. 6,096,597 to Tsu et al, 6,329,234B1 to Ma et al, and 6,271,084B1 to Tu et al show MIM capacitor processes. U.S. Pat. No. 6,211,061 to Chen et al teaches a dual damascene process with carbon-based low-k materials.